Early detection of colorectal cancer based on presence of methylated syndecan-2 (SDC2) in stool DNA

Background

Colorectal cancer (CRC) screening can effectively reduce disease-related mortality by detecting CRC at earlier stages. We have previously demonstrated that the presence of SDC2 methylation in stool DNA is significantly associated with the occurrence of CRC regardless of clinical stage. The aim of this study was to evaluate the clinical performance of stool DNA-based SDC2 methylation test for CRC.

Methods

Aberrant SDC2 methylation in stool-derived DNA was measured by linear target enrichment (LTE)-quantitative methylation-specific real-time PCR (qMSP). Duplicate reactions of meSDC2 LTE-qMSP test were performed for stool samples obtained from CRC patients representing all stages (0–IV) and asymptomatic individuals who were subsequently underwent colonoscopy examination. To determine the diagnostic value of test in CRC and control groups, sensitivity and specificity were evaluated by receiver operating characteristic curve analysis.

Results

Of 585 subjects who could be evaluated, 245 had CRC, 44 had various sizes of adenomatous polyps, and 245 had negative colonoscopy results. Stool DNA-based meSDC2 LTE-qMSP showed an overall sensitivity of 90.2% with AUC of 0.902 in detecting CRC (0–IV) not associated with tumor stage, location, sex, or age (P > 0.05), with a specificity of 90.2%. Sensitivity for detecting early stages (0-II) was 89.1% (114/128). This test also detected 66.7% (2/3) and 24.4% (10/41) of advanced and non-advanced adenomas, respectively.

Conclusions

Results of this study validated the capability of stool DNA based-SDC2 methylation test by LTE-qMSP for early detection of CRC patient with high specificity.

Trial registration

ClinicalTrials.gov, NCT03146520, Registered 10 May 2017, Retrospectively registered; however, control arm was prospectively registered.

Prognostic significance of gross extrathyroidal extension invading only strap muscles in differentiated thyroid carcinoma

Background

In the eighth edition of the AJCC staging system for differentiated thyroid carcinoma (DTC), minimal extrathyroidal extension (ETE) is no longer a determinant of T3 category. Instead, gross ETE invading only strap muscles has been designated as a new T3b category. The long-term prognosis of patients with DTC and gross ETE invading only strap muscles was investigated.

Methods

This was a retrospective analysis of patients who underwent thyroidectomy between 1996 and 2005. Differences in cancer-specific and recurrence-free survival according to extent of ETE were assessed.

Results

A total of 3174 patients with DTC were included. No significant differences were observed in 10-year cancer-specific survival among patients with no ETE (98·6 per cent), microscopic ETE (98·3 per cent) and gross ETE invading only strap muscles (98·9 per cent) (P = 0·375). The 10-year recurrence-free survival rate for patients with gross ETE invading only strap muscles (89·2 per cent) was shorter than that for patients with no ETE (93·7 per cent; P = 0·016), but similar to that of patients with microscopic ETE (90·3 per cent). In univariable analysis, patients with gross ETE invading only strap muscles had a significantly higher risk of recurrence than those with no ETE (hazard ratio (HR) 1·67, 95 per cent c.i. 1·10 to 2·55; P = 0·017). In multivariable analysis, gross ETE invading only strap muscles was not an independent predictor of recurrence (HR 1·09, 0·71 to 1·69; P = 0·685).

Conclusion

Although gross ETE invading only strap muscles may provide prognostic information about long-term recurrence, it does not affect mortality. The actual impact of gross ETE invading only strap muscles will be important in revising the staging system in the future.

Long-Term Effects of Bone Marrow-Derived Mesenchymal Stem Cells in Dextran Sulfate Sodium-Induced Murine Chronic Colitis

Background/Aims

Bone marrow-derived mesenchymal stem cells (BM-MSCs) have shown beneficial effects in experimental colitis models, but the underlying mechanisms are not fully understood. We investigated the long-term effects of BM-MSCs, particularly in mice with chronic colitis.

Methods

Chronic colitis was induced by administering 3% dextran sulfate sodium (DSS) in a series of three cycles. BM-MSCs were injected intravenously into DSS-treated mice three times during the first cycle. On day 33, the therapeutic effects were evaluated with clinicopathologic profiles and histological scoring. Inflammatory mediators were measured with real-time polymerase chain reaction.

Results

Systemic infusion of BM-MSCs ameliorated the severity of colitis, and body weight restoration was significantly promoted in the BM-MSC-treated mice. In addition, BM-MSC treatment showed a sustained beneficial effect throughout the three cycles. Microscopic examination revealed that the mice treated with BM-MSCs had fewer inflammatory infiltrates, a lesser extent of inflammation, and less crypt structure damage compared with mice with DSS-induced colitis. Anti-inflammatory cytokine levels of interleukin-10 were significantly increased in the inflamed colons of BM-MSC-treated mice compared with DSS-induced colitis mice.

Conclusions

Systemic infusion of BM-MSCs at the onset of disease exerted preventive and rapid recovery effects, with long-term immunosuppressive action in mice with repeated DSS-induced chronic colitis.

Accuracy of three different fecal calprotectin tests in the diagnosis of inflammatory bowel disease

Background/Aims

Several studies have found that the measurement of fecal calprotectin is useful for the early diagnosis of inflammatory bowel disease (IBD). We compared the effectiveness of three different fecal calprotectin kits for initial diagnosis in patients with suspected IBD.

Methods

We enrolled 31 patients with IBD (18 Crohn's disease [CD], 11 ulcerative colitis [UC], and two intestinal Behçet's disease), five with irritable bowel syndrome (IBS), and five with other colitis (four infectious colitis and one intestinal tuberculosis). Diagnosis was based on clinical, laboratory, and endoscopic examinations. Fecal samples were obtained at the first diagnosis and calprotectin levels were measured using three different kits (Quantum Blue® Calprotectin, EliA™ Calprotectin, and RIDASCREEN® Calprotectin).

Results

The overall accuracy for differentiating IBD from IBS or other colitis was 94% and 91%, respectively, for Quantum Blue® (cutoff, 50 µg/g); 92% and 89%, respectively, for EliA™ (cutoff, 50 µg/g); and 82% and 76%, respectively, for RIDASCREEN® (cutoff, 50 µg/g). In patients with CD, the results of Quantum Blue® Calprotectin and EliA™ Calprotectin correlated significantly with levels of the Crohn's disease activity index (Spearman's rank correlation coefficient, r=0.66 and r=0.49, respectively). In patients with UC, the results of EliA™ Calprotectin correlated significantly with the Mayo score (r=0.70).

Conclusions

Fecal calprotectin measurement is useful for the identification of IBD. The overall accuracies of the three fecal calprotectin kits are comparable.

Risk Factors for Recurrent High-Risk Polyps after the Removal of High-Risk Polyps at Initial Colonoscopy

PURPOSE

Colonoscopic polypectomy and surveillance are important to prevent colorectal cancer and identify additional relative risk factors for adequate surveillance. In this study, we evaluated risk factors related to recurrent high-risk polyps during the surveillance of patients with high-risk polyps.

MATERIALS AND METHODS

We included 434 patients who had high-risk polyps (adenoma≥10 mm, ≥3 adenomas, villous histology, or high-grade dysplasia) on the baseline colonoscopy and underwent at least one surveillance colonoscopy from 2005 to 2011 at Severance Hospital. Data regarding patient characteristics, bowel preparation and polyp size, location, number, and pathological diagnosis were retrospectively collected from medical records. Patients with recurrent high-risk polyps were compared with patients with low-risk or no polyps during surveillance.

RESULTS

Patients were predominantly male (77.4%), with a mean age of 61.0±8.6 years and mean follow-up of 1.5±0.8 years. High-risk polyps recurred during surveillance colonoscopy in 51 (11.8%) patients. Results of multivariate analysis showed that male gender, poor bowel preparation, and a larger number of adenomas were independent risk factors for recurrent high-risk polyps (p=0.047, 0.01, and <0.001, respectively). Compared with high-risk polyps found during initial colonoscopy, high-risk polyps on surveillance colonoscopy had higher proportions of small adenomas, low-risk pathology, and fewer adenomas overall, but there was no difference in location.

CONCLUSION

Male patients and those with poor bowel preparation for colonoscopy or higher numbers of adenomas were more likely to experience recurrent high-risk polyps.

GWAS identifies two susceptibility loci for lamotrigine-induced skin rash in patients with epilepsy

PURPOSE

Lamotrigine (LTG)-induced maculopapular eruption (MPE) often causes treatment discontinuation and rising burdens on current healthcare systems. We conducted a genome-wide association study to identify novel susceptibility loci associated with LTG-induced MPE in patients with epilepsy.

MATERIALS AND METHODS

We enrolled patients with LTG-induced MPE (n=34) and utilized the Korea Association Resource project cohort as a control group (n=1214). We explored associations between LTG-induced MPE and single nucleotide polymorphisms (SNPs) through imputation and replicated these associations in samples from 59 LTG-induced MPE cases and 98 LTG tolerant-controls.

RESULTS

We found two novel SNPs associated with LTG-induced MPE: rs12668095 near CRAMP1L/TMEM204/IFT140/HN1L (P=4.89×10(-7)) and rs79007183 near TNS3 (P=3.15×10(-10)), both of which were replicated in an independent cohort.

CONCLUSION

These two validated SNPs may be good candidate markers for predicting LTG-induced MPE in epilepsy patients, although further experimental validation is needed.

Correlation between soluble triggering receptor expressed on myeloid cells-1 and endoscopic activity in intestinal Behçet's disease

PURPOSE

The serum levels of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) have recently been shown to be correlated highly with disease activity in patients with intestinal Behçet's disease (BD). However, it remains unclear whether sTREM-1 levels reflect endoscopic activity in intestinal BD. This study aimed to evaluate the correlation of sTREM-1 levels with endoscopic activity in intestinal BD.

MATERIALS AND METHODS

A total of 84 patients with intestinal BD were enrolled. Endoscopic activity was compared with sTREM-1 levels as well as other laboratory findings, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).

RESULTS

sTREM-1 levels were significantly increased in intestinal BD patients compared with controls (37.98±27.09 pg/mL vs. 16.65±7.76 pg/mL, p=0.002), however, there was no difference between endoscopically quiescent and active diseases (43.53±24.95 pg/mL vs. 42.22±32.68 pg/mL, p=0.819). Moreover, serum sTREM-1 levels did not differ in terms of number, shape, depth, size, margin, or type of ulcer in patients with intestinal BD. However, mean ESR and CRP levels in patients with active disease were significantly higher than those in patients with quiescent disease (p=0.001, p<0.001, respectively). In addition, endoscopic activity scores for intestinal BD were correlated significantly with both CRP levels (γ=0.329) and ESR (γ=0.298), but not with sTREM-1 levels (γ=0.166).

CONCLUSION

Unlike CRP levels and ESR, serum sTREM-1 levels were not correlated with endoscopic activity in patients with intestinal BD.

Endoscopic papillary large balloon dilatation alone is safe and effective for the treatment of difficult choledocholithiasis in cases of Billroth II gastrectomy: a single center experience

BACKGROUND

Endoscopic treatment of difficult common bile duct (CBD) stones (diameter ≥ 10 mm, or four or more) is difficult in patients who have undergone Billroth II (B-II) gastrectomy. Endoscopic sphincterotomy (EST) can be particularly troublesome due to anatomical changes effected by the gastrectomy.

AIM

We evaluated the efficacy and safety of endoscopic papillary large balloon dilation (EPLBD) with large-diameter dilation balloons in the treatment of difficult CBD stones in patients who have undergone B-II gastrectomy.

MATERIALS AND METHODS

From June 2006 to April 2011, patients with difficult CBD stones and who had undergone B-II gastrectomy previously were included in this study. EPLBD was performed with a 10-18 mm balloon catheter. When selective cannulation through the sphincter was possible, EPLBD was performed without EST. EPLBD was otherwise performed after fistulotomy with needle knife.

RESULTS

A total of 40 patients (32 male) underwent EPLBD for the retrieval of CBD stones, and concurrent fistulotomy was performed in seven patients. The median diameter of CBD was 13 mm (range 10-20 mm) and the balloon was 12 mm (range 10-17 mm). CBD stones were successfully removed in all patients. In only three patients, repeated sessions of ERCP were required for complete removal of CBD stones. Mechanical lithotripsy was required in only one case. Acute complications from EPLBD included mild pancreatitis in two patients (5.0 %). Severe complications, including perforation and bleeding, were not observed. Late complications included stone recurrence in one patient (2.5 %) and cholecystitis in four patients (10.0 %).

CONCLUSIONS

In cases of B-II gastrectomy, EPLBD without EST is a safe and highly effective technique for the retrieval of difficult CBD stones. EPLBD should be considered as an alternative tool to conventional EST.

Clinical outcomes following secondary self-expandable metal stent (SEMS) insertion due to previous stent migration in malignant colorectal obstruction

BACKGROUND

There has been no research on the clinical outcomes of secondary self-expandable metal stent (SEMS) placement after initial stent migration. Therefore, this study aimed to assess the clinical outcomes of secondary SEMS placement after initial stent migration compared to the outcomes of secondary SEMS placement done for reasons other than migration and identify factors predictive of long-term outcomes.

METHODS

Between January 2005 and February 2011, a total of 422 patients underwent SEMS insertion for malignant colorectal obstruction at Severance Hospital. Of these, there were 98 cases of secondary SEMS placement, 38 of which were due to previous stent migration. We compared the clinical outcomes of secondary SEMS between stent migration and nonmigration groups. We also sought to identify risk factors for long-term outcomes of secondary SEMS after initial stent migration.

RESULTS

The baseline clinical characteristics were similar between the two groups. The technical and clinical success rates of secondary SEMS insertion in the migration and nonmigration groups were 94.7% and 83.3% (p = 0.09) and 73.7% and 53.3% (p = 0.122), respectively. In the migration group, sustained clinical success after secondary SEMS was associated with the absence of complications after insertion of the first stent (p < 0.001) and a longer time interval (more than 100 days) between the first and second stent insertion (p = 0.011).

CONCLUSIONS

Our data showed that secondary colorectal SEMS after stent migration is safe and effective. Moreover, the sustained clinical success of the secondary stent following migration was dependent on the outcomes of the first stent.

Folfox4 as a rescue chemotherapy for gemcitabine-refractory pancreatic cancer

BACKGROUND/AIMS

This phase II study assessed the efficacy and safety of FOLFOX4 as a rescue therapy in patients with gemcitabine-refractory pancreatic cancer.

METHODOLOGY

The study included patients with advanced pancreatic cancer who had failed gemcitabine-based chemotherapy. FOLFOX4 was administered biweekly as follows: oxaliplatin, 85 mg/m² as a 2-hour infusion (day 1); leucovorin, 200 mg/m²/day as a 2-hour infusion (days 1 and 2); 5-fluorouracil, bolus 400 mg/m²/day and 600 mg/m²/day as a 22-hour infusion (days 1 and 2).

RESULTS

Forty-four patients received a total of 264 cycles of chemotherapy. There was 1 complete response (2.2%), 4 partial responses (9.1%), and 13 stable diseases (29.5%). The objective response rate was 11.4% and the tumor stabilization rate was 40.9%. The median time to progression was 9.9 weeks (95%CI: 8.2-11.5) and the median overall survival was 31.1 weeks (95%CI: 24.4-37.9). The common adverse events were hematologic toxicities: grade 3 or 4 neutropenia in 19 patients (43.2%), anemia in 9 patients (20.5%), and thrombocytopenia in 6 patients (13.5%). Grade 3 or 4 neuropathy occurred in 4 patients (9.1%).

CONCLUSIONS

In gemcitabine-refractory pancreatic cancer, FOLFOX4 showed encouraging activity and was generally well-tolerated. However, careful attention needs to be paid to hematologic toxicities.

Clinical outcomes and predictive factors in oral corticosteroid-refractory active ulcerative colitis

AIM: To evaluate the clinical outcomes and prognostic factors after intravenous corticosteroids following oral corticosteroid failure in active ulcerative colitis patients.

METHODS: Consecutive patients with moderate to severe ulcerative colitis who had been treated with a course of intravenous corticosteroids after oral corticosteroid therapy failure between January 1996 and July 2010 were recruited at Severance Hospital, Seoul, South Korea. The disease activity was measured by the Mayo score, which consists of stool frequency, rectal bleeding, mucosal appearance at flexible sigmoidoscopy, and Physician Global Assessment. We retrospectively evaluated clinical outcomes at two weeks, one month, three months, and one year after the initiation of intravenous corticosteroid therapy. Two weeks outcomes were classified as responders or non-responders. One month, three month and one year outcomes were classified into prolonged response, steroid dependency, and refractoriness.

RESULTS: Our study included a total of 67 eligible patients. At two weeks, 56 (83.6%) patients responded to intravenous corticosteroids. At one month, complete remission was documented in 18 (32.1%) patients and partial remission in 26 (46.4%). Eleven patients (19.7%) were refractory to the treatment. At three months and one year, we found 37 (67.3%) and 25 (46.3%) patients in prolonged response, ten (18.2%) and 23 (42.6%) patients in corticosteroid dependency, 8 (14.5%) and 6 (11.1%) patients with no response, respectively. Total 9 patients were underwent elective proctocolectomy within 1 year. The duration of oral corticosteroid therapy (> 14 d vs≤ 14 d, P = 0.049) and lower hemoglobin level (≤ 11.0 mg/dL vs >11.0 mg/dL, P = 0.02) were found to be poor prognostic factors for response at two weeks. For one year outcome, univariate analysis revealed that only a partial Mayo score (≥ 6 vs <6, P = 0.057) was found to be associated with a poor response.

CONCLUSION: The duration of oral corticosteroid therapy and lower hemoglobin level were strongly associated with poor outcome.

Correlations between endoscopic and clinical disease activity indices in intestinal Behcet's disease

AIM: To develop a novel endoscopic severity model of intestinal Behcet's disease (BD) and to evaluate its feasibility by comparing it with the actual disease activity index for intestinal Behcet's disease (DAIBD).

METHODS: We reviewed the medical records of 167 intestinal BD patients between March 1986 and April 2011. We also investigated the endoscopic parameters including ulcer locations, distribution, number, depth, shape, size and margin to identify independent factors associated with DAIBD. An endoscopic severity model was developed using significant colonoscopic variables identified by multivariate regression analysis and its correlation with the DAIBD was evaluated. To determine factors related to the discrepancy between endoscopic severity and clinical activity, clinical characteristics and laboratory markers of the patients were analyzed.

RESULTS: A multivariate regression analysis revealed that the number of intestinal ulcers (≥ 2, P = 0.031) and volcanoshaped ulcers (P = 0.001) were predictive factors for the DAIBD. An endoscopic severity model (Y) was developed based on selected endoscopic variables as follows: Y = 47.44 + 9.04 × non-Ileocecal area + 11.85 ×≥ 2 of intestinal ulcers + 5.03 × shallow ulcers + 12.76 × deep ulcers + 4.47 × geographic-shaped ulcers + 26.93 × volcano-shaped ulcers + 8.65 ×≥ 20 mm of intestinal ulcers. However, endoscopic parameters used in the multivariate analysis explained only 18.9% of the DAIBD variance. Patients with severe DAIBD scores but with moderately predicted disease activity by the endoscopic severity model had more symptoms of irritable bowel syndrome (21.4% vs 4.9%, P = 0.026) and a lower rate of corticosteroid use (50.0% vs 75.6%, P = 0.016) than those with severe DAIBD scores and accurately predicted disease by the model.

CONCLUSION: Our study showed that the number of intestinal ulcers and volcano-shaped ulcers were predictive factors for severe DAIBD scores. However, the correlation between endoscopic severity and DAIBD (r = 0.434) was weak.

How many valid measurements are necessary to assess liver fibrosis using FibroScan® in patients with chronic viral hepatitis? An analysis of subjects with at least 10 valid measurements

PURPOSE

Using FibroScan® to obtain a reliable liver stiffness measurement (LSM) may require more than 10 valid measurements (VMs), according to the manufacturer's recommendations. However, this requirement lacks scientific evidence in support thereof. We investigated the minimal number of VMs required to assess liver fibrosis without significant loss of accuracy in patients with chronic hepatitis B (CHB) and C (CHC) and predictors of discordance between LSM and liver biopsy (LB).

MATERIALS AND METHODS

Between January 2005 and December 2009, we prospectively enrolled 182 patients with CHB and 68 patients with CHC who were to undergo LB and LSM before starting antiviral treatment. Only LSMs with at least 10 VMs were considered reliable. The Batts and Ludwig scoring system was used for histologic assessment.

RESULTS

The mean age and body mass index were 46.0 years and 23.4 kg/m² in patients with CHB and 49.7 years and 23.1 kg/m² in those with CHC, respectively. The median elasticity scores from the first 3, first 5, and all VMs taken significantly predicted fibrosis stages ≥F2 and F4 (all p<0.05) without significant differences (all p>0.05 by DeLong's method). Alanine aminotransferase (ALT) was the only predictor of discordance in fibrosis stage as estimated by the median elasticity score from the first 3 VMs and by LB in patients with CHB, whereas no significant predictor was identified in those with CHC.

CONCLUSION

After comparison of patients who had more than 10 valid measurements for LSM, three VMs may be enough to assess liver fibrosis using LSM without significant loss of accuracy in patients with CHC and patients with CHB. However, ALT should be considered when interpreting LSM for patients with CHB.

Giant piezoelectricity on Si for hyperactive MEMS

Microelectromechanical systems (MEMS) incorporating active piezoelectric layers offer integrated actuation, sensing, and transduction. The broad implementation of such active MEMS has long been constrained by the inability to integrate materials with giant piezoelectric response, such as Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3) (PMN-PT). We synthesized high-quality PMN-PT epitaxial thin films on vicinal (001) Si wafers with the use of an epitaxial (001) SrTiO(3) template layer with superior piezoelectric coefficients (e(31,f) = -27 ± 3 coulombs per square meter) and figures of merit for piezoelectric energy-harvesting systems. We have incorporated these heterostructures into microcantilevers that are actuated with extremely low drive voltage due to thin-film piezoelectric properties that rival bulk PMN-PT single crystals. These epitaxial heterostructures exhibit very large electromechanical coupling for ultrasound medical imaging, microfluidic control, mechanical sensing, and energy harvesting.

Factors affecting insertion time for colonoscopy performed under intramuscular analgesia in patients with history of colorectal resection

BACKGROUND

Colonoscopy can detect both early intraluminal recurrence and metachronous neoplasia after colorectal cancer resection. Because colon length and location change after colorectal resection, factors affecting insertion time during colonoscopy also might be altered. The goal of this study was to examine whether colonoscope insertion time differs between left-sided resection and right-sided resection and to identify factors that impact the performance of colonoscopy after colorectal resection.

METHODS

We included consecutive patients who underwent colonoscopy between November 2005 and November 2009 after colorectal resection for colorectal cancer. We classified surgical methods into left-sided resection (left hemicolectomy, low anterior resection, anterior resection, Hartman, and Mile's operation) or right-sided resection (right hemicolectomy) and retrospectively evaluated the colonoscope insertion time. Moreover, we analyzed factors that might affect the insertion time.

RESULTS

A total of 1,260 patients underwent colonoscopy after colorectal resection during the study period. Of these, 1,248 patients (771 men) who underwent complete colonoscopy were evaluated in this study. The colonoscopy completion rate was 99%, and the mean insertion time was 6.5±5.1 min (median, 5 min; range, 0.3-61 min). Right-sided resection, female gender, poor quality of bowel preparation, lower endoscopist case volume, open laparotomy, and colonoscopy performed more than 1 year after colorectal resection were found to be independent factors associated with prolonged insertion time.

CONCLUSIONS

This large study identified six factors that affect colonoscope insertion time after colorectal resection. These findings have implications for the practice and teaching of colonoscopy after colorectal resection.

The usefulness of liver stiffness measurement using FibroScan in chronic hepatitis C in South Korea: a multicenter, prospective study

AIM

We investigated the accuracy of liver stiffness measurement (LSM) in chronic hepatitis C (CHC) in a multicenter, prospective study in South Korea.

METHODS

Between June 2005 and July 2009, 91 CHC patients without a previous history of antiviral treatment, clinical evidences of cirrhosis, coinfection with other viruses, and heavy alcohol consumption and with alanine aminotransferase (ALT) ≤5x upper limit of normal, total bilirubin ≤1.5 mg/dL, sufficient liver biopsy quality (≥15 mm and more than six portal tracts), interquartile range to median liver stiffness (LS) value ratio ≤0.21, and more than 10 valid measurements, were recruited. The Batts and Ludwig scoring system was used for histologic assessment. Age-platelet index (API), aspartate aminotransferase (AST)-to-platelet ratio index (APRI), and age-spleen-platelet ratio index (ASPRI) were calculated. Area under the receiver operating characteristic curve (AUROC) was used to evaluate the performance of LSM and other noninvasive models.

RESULTS

The mean age was 47.9 years, and the mean LS value was 7.7 kPa (44 men and 47 women). LS value was highly correlated to the fibrosis stages (r=0.835, P<0.001). The AUROCs of LSM were 0.909 for ≥F2, 0.993 for ≥F3, and 0.970 for F=4 and were superior to those of API (0.72, 0.858, and 0.948, respectively), APRI (0.780, 0.887, and 0.904, respectively), and ASPRI (0.713, 0.862, and 0.957, respectively). The optimal cutoff LS values were 6.2 kPa for ≥F2, 7.7 kPa for ≥F3, and 11.0 kPa for F=4.

CONCLUSIONS

Our data suggest that LSM can accurately assess liver fibrosis in patients with CHC and be applied in South Korea.

Risk Factors for Treatment Failure and Recurrence after Metronidazole Treatment for Clostridium difficile-associated Diarrhea

BACKGROUND/AIMS

The incidence of treatment failure or recurrence of Clostridium difficile-associated diarrhea (CDAD) following metronidazole treatment has increased recently. We studied the treatment failure, recurrence rate, and risk factors predictive of treatment failure and recurrence after metronidazole treatment for CDAD.

METHODS

We retrospectively identified consecutive patients who were admitted and treated for CDAD at a single tertiary institution in Korea over a recent 10-year period (i.e., 1998-2008).

RESULTS

Metronidazole was administered as the initial treatment to 111 of 117 patients (94.9%) with CDAD. Fourteen patients (12.6%) had no clinical response to the metronidazole treatment, and in 13 patients (13.4%) CDAD recurred after successful metronidazole treatment. Diabetes mellitus (p=0.014) and sepsis (p=0.002) were independent risk factors for metronidazole treatment failure. Patients who had received surgery within 1 month before CDAD developed were more likely to experience a recurrence after metronidazole treatment (p=0.032). Vancomycin exhibited a higher response rate after treatment failure, and metronidazole showed a reasonable response rate in the treatment of recurrence. Treatment failure and recurrence rates increased with time after metronidazole treatment for CDAD over the 10-year study period.

CONCLUSIONS

Our data suggest that diabetes mellitus and sepsis are independent risk factors for metronidazole treatment failure, and that operation history within 1 month of development of CDAD is a predictor of a recurrence after metronidazole treatment.

Risk Factors for Treatment Failure and Recurrence after Metronidazole Treatment for Clostridium difficile-associated Diarrhea

BACKGROUND/AIMS

The incidence of treatment failure or recurrence of Clostridium difficile-associated diarrhea (CDAD) following metronidazole treatment has increased recently. We studied the treatment failure, recurrence rate, and risk factors predictive of treatment failure and recurrence after metronidazole treatment for CDAD.

METHODS

We retrospectively identified consecutive patients who were admitted and treated for CDAD at a single tertiary institution in Korea over a recent 10-year period (i.e., 1998-2008).

RESULTS

Metronidazole was administered as the initial treatment to 111 of 117 patients (94.9%) with CDAD. Fourteen patients (12.6%) had no clinical response to the metronidazole treatment, and in 13 patients (13.4%) CDAD recurred after successful metronidazole treatment. Diabetes mellitus (p=0.014) and sepsis (p=0.002) were independent risk factors for metronidazole treatment failure. Patients who had received surgery within 1 month before CDAD developed were more likely to experience a recurrence after metronidazole treatment (p=0.032). Vancomycin exhibited a higher response rate after treatment failure, and metronidazole showed a reasonable response rate in the treatment of recurrence. Treatment failure and recurrence rates increased with time after metronidazole treatment for CDAD over the 10-year study period.

CONCLUSIONS

Our data suggest that diabetes mellitus and sepsis are independent risk factors for metronidazole treatment failure, and that operation history within 1 month of development of CDAD is a predictor of a recurrence after metronidazole treatment.

Spin injection/detection using an organic-based magnetic semiconductor

The new paradigm of electronics, 'spintronics', promises to extend the functionality of information storage and processing in conventional electronics. The principal spintronics device, the 'spin valve', consists of two magnetic layers decoupled by a spin-transporting spacer, which allows parallel (on) and antiparallel (off) alignment of the magnetizations (spins) of the two magnetic layers. The device resistance then depends on the spin alignment controlled by the external magnetic field. In pursuit of semiconductor spintronics, there have been intensive efforts devoted to develop room-temperature magnetic semiconductors and also to incorporate both inorganic semiconductors and carbon-based materials as the spin-transporting channels. Molecule/organic-based magnets, which allow chemical tuning of electronic and magnetic properties, are a promising new class of magnetic materials for future spintronic applications. Here, we report the realization of an organic-based magnet as an electron spin polarizer in the standard spintronics device geometry. A thin non-magnetic organic semiconductor layer and an epitaxial ferromagnetic oxide film were employed to form a hybrid magnetic tunnel junction. The results demonstrate the spin-polarizing nature of the organic-based magnetic semiconductor, vanadium(TCNE: tetracyanoethylene)(x) (x approximately 2; T(c) approximately 400 K), and its function as a spin injector/detector in hybrid magnetic multilayer devices.

Ferroelectricity in strain-free SrTiO3 thin films

Biaxial strain is known to induce ferroelectricity in thin films of nominally nonferroelectric materials such as SrTiO3. By a direct comparison of the strained and strain-free SrTiO3 films using dielectric, ferroelectric, Raman, nonlinear optical and nanoscale piezoelectric property measurements, we conclude that all SrTiO3 films and bulk crystals are relaxor ferroelectrics, and the role of strain is to stabilize longer-range correlation of preexisting nanopolar regions, likely originating from minute amounts of unintentional Sr deficiency in nominally stoichiometric samples. These findings highlight the sensitive role of stoichiometry when exploring strain and epitaxy-induced electronic phenomena in oxide films, heterostructures, and interfaces.

Template engineering of Co-doped BaFe2As2 single-crystal thin films

Understanding new superconductors requires high-quality epitaxial thin films to explore intrinsic electromagnetic properties and evaluate device applications. So far, superconducting properties of ferropnictide thin films seem compromised by imperfect epitaxial growth and poor connectivity of the superconducting phase. Here we report new template engineering using single-crystal intermediate layers of (001) SrTiO(3) and BaTiO(3) grown on various perovskite substrates that enables genuine epitaxial films of Co-doped BaFe(2)As(2) with a high transition temperature (T(c,rho=0) of 21.5 K, where rho=resistivity), a small transition width (DeltaT(c)=1.3 K), a superior critical current density J(c) of 4.5 MA cm(-2) (4.2 K) and strong c-axis flux pinning. Implementing SrTiO(3) or BaTiO(3) templates to match the alkaline-earth layer in the Ba-122 with the alkaline-earth/oxygen layer in the templates opens new avenues for epitaxial growth of ferropnictides on multifunctional single-crystal substrates. Beyond superconductors, it provides a framework for growing heteroepitaxial intermetallic compounds on various substrates by matching interfacial layers between templates and thin-film overlayers.

Ferroelastic switching for nanoscale non-volatile magnetoelectric devices

Multiferroics, where (anti-) ferromagnetic, ferroelectric and ferroelastic order parameters coexist, enable manipulation of magnetic ordering by an electric field through switching of the electric polarization. It has been shown that realization of magnetoelectric coupling in a single-phase multiferroic such as BiFeO(3) requires ferroelastic (71 degrees, 109 degrees) rather than ferroelectric (180 degrees) domain switching. However, the control of such ferroelastic switching in a single-phase system has been a significant challenge as elastic interactions tend to destabilize small switched volumes, resulting in subsequent ferroelastic back-switching at zero electric field, and thus the disappearance of non-volatile information storage. Guided by our phase-field simulations, here we report an approach to stabilize ferroelastic switching by eliminating the stress-induced instability responsible for back-switching using isolated monodomain BiFeO(3) islands. This work demonstrates a critical step to control and use non-volatile magnetoelectric coupling at the nanoscale. Beyond magnetoelectric coupling, it provides a framework for exploring a route to control multiple order parameters coupled to ferroelastic order in other low-symmetry materials.

Tunneling electroresistance effect in ferroelectric tunnel junctions at the nanoscale

Using a set of scanning probe microscopy techniques, we demonstrate the reproducible tunneling electroresistance effect on nanometer-thick epitaxial BaTiO(3) single-crystalline thin films on SrRuO(3) bottom electrodes. Correlation between ferroelectric and electronic transport properties is established by direct nanoscale visualization and control of polarization and tunneling current. The obtained results show a change in resistance by about 2 orders of magnitude upon polarization reversal on a lateral scale of 20 nm at room temperature. These results are promising for employing ferroelectric tunnel junctions in nonvolatile memory and logic devices.

Strain-induced polarization rotation in epitaxial (001) BiFeO3 thin films

Direct measurement of the remanent polarization of high quality (001)-oriented epitaxial BiFeO3 thin films shows a strong strain dependence, even larger than conventional (001)-oriented PbTiO3 films. Thermodynamic analysis reveals that a strain-induced polarization rotation mechanism is responsible for the large change in the out-of-plane polarization of (001) BiFeO3 with biaxial strain while the spontaneous polarization itself remains almost constant.

Magnetic color symmetry of lattice rotations in a diamagnetic material

Oxygen octahedral rotations are the most common phase transitions in perovskite crystal structures. Here we show that the color symmetry of such pure elastic distortions is isomorphic to magnetic point groups, which allows their probing through distinguishing polar versus magnetic symmetry. We demonstrate this isomorphism using nonlinear optical probing of the octahedral rotational transition in a compressively strained SrTiO3 thin film that exhibits ferroelectric (4mm) and antiferrodistortive (4{'}mm{'}) phases evolving through independent phase transitions. The approach has broader applicability for probing materials with lattice rotations that can be mapped to color groups.

Enhanced secretion of Bacillus stearothermophilus L1 lipase in Saccharomyces cerevisiae by translational fusion to cellulose-binding domain

The secretion of Bacillus stearothermophilus L1 lipase in Saccharomyces cerevisiae was investigated by employing a fusion partner, a cellulose-binding domain (CBD) from Trichoderma harzianum endoglucanase II (THEG). The CBD was connected to the N-terminal of L1 lipase through an endogenous linker peptide from THEG. The expression cassette for the fusion protein in S. cerevisiae was constructed using the alpha-amylase signal peptide and the galactose-inducible GAL10 promoter. Secretion of CBD-linker-L1 lipase by this fusion construct was dramatically 7-fold enhanced, compared with that of the mature L1 lipase without CBD-fusion. The fusion protein was secreted into the culture medium, reaching levels of approximately 1.3 g/l in high-cell-density fed-batch cultures. Insertion of a KEX2 cleavage site into the junction between CBD-linker and L1 lipase resulted in the same level of enhanced secretion, indicating that the CBD-linker fusion probably plays a critical role in secretion from endoplasmic reticulum to Golgi apparatus. Therefore, the CBD from THEG can be used both as an affinity tag and as a secretion enhancer for the secretory production of heterologous proteins in S. cerevisiae, since in vivo breakage at the linker was almost negligible.

Transduction of Cu,Zn-superoxide dismutase mediated by an HIV-1 Tat protein basic domain into mammalian cells

A human Cu,Zn-superoxide dismutase (Cu,Zn-SOD) gene was fused with a gene fragment encoding the nine amino acid transactivator of transcription (Tat) protein transduction domain (RKKRRQRRR) of HIV-1 in a bacterial expression vector to produce a genetic in-frame Tat-SOD fusion protein. The expressed and purified Tat-SOD fusion protein in Escherichia coli can enter HeLa cells in a time- and dose-dependent manner when added exogenously in a culture media. Denatured Tat-SOD protein was transduced much more efficiently into cells than were native proteins. Once inside the cells, transduced Tat-SOD protein was enzymatically active and stable for 24 h. The cell viability of HeLa cells treated with paraquat, an intracellular superoxide anion generator, was increased by transduced Tat-SOD. These lines of results suggest that the transduction of Tat-SOD fusion protein may be one of the ways to replenish the Cu,Zn-SOD in the various disorders related to this antioxidant enzyme.